Epidemiologists investigated the transmission of the measles virus (a highly infectious viral pathogen) following an exposure event. A group of 40 children attended an indoor trampoline park party on Day 0. On the day of the party, one child was infectious with measles.
Over the next three weeks, health officials monitored the remaining 39 children and recorded the day on which each child first developed the characteristic measles rash. The results are shown in Table 1 below.
Table 1
| Day when measles rash first showed | Number of children |
|---|---|
| 6 | 0 |
| 8 | 1 |
| 10 | 4 |
| 12 | 15 |
| 14 | 8 |
| 16 | 2 |
| 18 | 0 |
| 20 | 0 |
| Total | 30 |
What was the range of days on which children first showed the measles rash? Use the data in Table 1.
From day ____________ to day ____________
The incubation time is the period between initial exposure to a pathogen and the first appearance of clinical symptoms. Suggest the most likely incubation time for measles based on this cohort.
Incubation time = ____________ days
Suggest one reason why some of the children who were exposed at the party did not develop measles.